Skip to Content

How to Get Rid of Foam in a Hot Tub Naturally

By: Author Jeff Campbell

Posted on  - Last updated:

Categories Hot Tub Water Chemistry

All hot tub owners eventually encounter hot tub foam. But what causes it? Is it harmful? Do we have to drain the hot tub to get rid of it? Don’t worry. Here’s how to get rid of foam in a hot tub naturally.

Eliminate hot tub foam naturally by ensuring the pH is balanced, hyper-chlorinating the water, using a defoamer, and ensuring the filters are rinsed clean.

I have had over 15 years of experience owning hot tubs, so I know that feeling well. I also know what causes this phenomenon and the best ways to fix it.

Ready to Spend Less Time On Maintenance and More Time Enjoying Your Hot Tub?

Let’s face it. Balancing the water, cleaning filters, dealing with rashes, and trying to figure out which chemicals to buy and add can make you feel more like a chemist than someone who just wants to relax after a long hard day!

That’s exactly why The Hot Tub Handbook and Video Course is so valuable!

This is from Matt over at Swim University and he developed it for people looking to save money, time, and frustration. His tips on chemicals can save you $100/year just by making sure you buy only what you need.

So if you’re ready to stop being confused or frustrated with your hot tub and start spending more time in it, check out The Hot Tub Handbook and Video Course.

Just click that link to learn more on their website.

So, let’s not waste any more time. Jump in and find out what you need to do to prevent a foam build-up and how to get rid of it if that fails.

get rid of foam lg

What causes excessive foam in a hot tub?

Foamy water in a hot tub is usually a result of excessive amounts of what’s known as total dissolved solids or TDS for short. This is made up of things such as makeup, soap residue, remnants of laundry detergent on bathing suits, deodorant, body lotions, body oils, and shampoo.

Showering before getting into the hot tub can help eliminate much of this, but there are still things that will add to the TDS and cause the water to foam. Sweat, flaking skin, and hair cannot be avoided no matter how much you shower beforehand.

Nature can also add to the problem with dead leaves and blossoms from nearby trees, insects, and algae build-up.

Foam on the surface of the water could indicate that there is a chemical imbalance and the pH is too high.

Check your pH and alkalinity levels regularly with a test strip and adjust accordingly to prevent the water from foaming. I recommend the Poolmaster 4-Way test strips from Amazon. Click on the link to check the latest prices.

Another cause of foam could be the hardness of the water. Low calcium levels can lead to fittings corroding, so it is important that this is also checked.

So, if you have a whole house water softener and the hose goes through that, this is likely your culprit.

Use the test strips to check if you have soft water. If it is low, a hardness increaser such as calcium chloride (road salt) should be added to the water but only in small amounts as this can irritate the skin. Sodium bicarbonate (baking soda) also increases hardness.

I wrote a recent article on the causes of excessive foam, and you can see that here on my website by clicking on the link.

How do I stop my hot tub from foaming?

Ensuring proper sanitizer levels and balanced pH levels will usually do the trick. Adding sanitizer such as chlorine or bromine each day or after every session, if you’re not a frequent user, is the best way to keep the water clean, clear, and foam-free.

Other things you should do include:

  • Removing and cleaning your hot tub filter at least every 3 weeks. This is just a matter of hosing it down and getting into the folds.
  • Checking the pH and alkalinity levels every other day or before getting in to make sure the balance is right.
  • Changing the water and thoroughly cleaning your hot tub every 3 to 4 months. At this time, you should give your filter a deep clean as well by soaking it in a 5-gallon bucket of water with a cleaning agent overnight. Fresh water will always fix the issue.
  • Shocking the water once a week.

You should shock your hot tub after heavy usage and at least once a week during normal use. Also, clean the filter to remove any contaminants. This way, the chemicals act more effectively at keeping your water crystal clear.

Shocking your hot tub is the process of adding a good dose of chlorine to reactivate the chlorine or bromine in the water.

You can read more about this in a recent article posted here on my website. Just click on the link to read the full article.

Another problem you might encounter when you lift the lid off your hot tub is finding the water cloudy and smelling of bad eggs. If you ever come across this, you should read the recent article here on my website by clicking on the link.

Once again, poor sanitization is usually the root cause of cloudy, smelly water. Bacteria in your hot tub build up to create a biofilm that clings to the pipework and clogs up the filter.

Will hot tub foam go away on its own?

No. If you do nothing at all, the foam will not only remain but will also get worse.

Of course, you’re not going to let that happen, are you? If you follow the routine described above, the foam will eventually disappear.

However, that could take some time, and you may find the foam comes back after a few days. That’s because you didn’t get to the cause of the problem—you dealt with the symptoms but didn’t cure the ailment.

Adding sanitizer regularly and shocking the water once a week should deal with the biofilm issue, but if you’re in an area where the water is soft or you used water that had gone through a softener to fill your hot tub, you’ll need to address this issue.

Some test strips will tell you how hard your water is by measuring the amount of calcium carbonate in there. Anything below 60 parts per million (PPM) is generally considered soft. Ideally, the amount of calcium carbonate should be no lower than 150 PPM.

Low calcium levels can lead to fittings corroding, so it is important that you deal with this.

Test strips will also measure the pH and Total Alkalinity (TA). Hard water typically has a pH level of 8.5 PPM and above, so if it is less than this, the water could be too soft. The ideal range of pH for hot tubs is 7.2 – 7.8, so if the reading is more than 8, you may have another issue to deal with.

Chlorine is much less effective at higher pH levels and is only 15% effective at a pH of 8.2. It is a balancing act for sure, you get one thing right, and something else goes out of kilter, but don’t worry, you’ll soon get the hang of it.

What is a hot tub defoamer (and is it natural)?

Hot Tub & Spa Defoamer is a silicone-based emulsion that eliminates foam without the use of harsh chemicals such as chlorine (although it’s essential to use a sanitizer in addition to this). Made with hydrophobic silica, it safely defoams hot tubs without altering the water chemistry.

CLICK HERE to check the current price on Amazon.

Is it natural? Not necessarily, but it shouldn’t contain any harsh chemicals either.

It is even safe to use it in an inflatable hot tub, and it doesn’t leave behind residue or cloudy water. And because it’s silicone-based, it won’t irritate the eyes and skin, making it safe for use in kid’s pools.

Hot Tub & Spa Defoamer works with chlorine, bromine, and mineral sanitizers, but it isn’t as effective with saltwater hot tubs.

If you have a problem with foamy hot tub water, this product will clear it quickly.

Add just one ounce and leave it a few minutes with the jets running before getting in. Add a little more as necessary if the foam doesn’t clear immediately.

Anti-foam products do exactly what it says on the bottle. It eliminates the foam from the surface of the water in your hot tub.

It is always a good idea to find out what is causing the foam in the first place. Many people buy products to get rid of a problem and then wonder why it keeps coming back.

It is normal to get a bit of foam on the surface when you turn your jets on full, but when you turn them off, it should disperse—if it doesn’t, you need to find out what’s causing it, and deal with it, as I explained above.

One of the most popular products around is Hot tub & Spa Defoamer by Essential Values. Check this out on Amazon by clicking on the link.

How much defoamer do I need for a hot tub?

This largely depends on the size of your hot tub and how bad the foaming is. Some manufacturers state that just 1 ounce will do the trick, whereas others quote 1 ounce per 100 gallons of water. So, for a 250-gallon hot tub, you’ll need 2½ ounces or about a third of a cup.

While defoamer is good at getting rid of the foam on the surface of your hot tub water, it isn’t a sanitizer and should never be used as a substitute for chlorine or bromine.

If you still have a problem after adding the recommended amount for your size of tub, you shouldn’t keep on adding more as this could make the water cloudy. It’s better to check everything else out, as discussed earlier.

Pay special attention to your filter, as this is your first line of defense. This is where all the nasty things get caught to prevent them from entering your plumbing system or being recycled into the tub.

You should always check pH and TA levels and add sanitizer regularly. If these all balance out, you shouldn’t need to add any more defoamer than recommended by the manufacturer.

What is a natural defoamer to use in a hot tub?

One thing I can pretty much guarantee most people will have in their kitchen is vinegar. I’ve mentioned in a few articles how good vinegar is at cleaning the surface of hot tubs, but did you know it can be used to get rid of foam?

White vinegar works best because there are fewer impurities than malt vinegar, or you could try Lucy’s Distilled Vinegar (click on the link to check the current price on Amazon). This product is 5% white vinegar distilled with water.

Here’s what to do:

Start by shocking the water, adding between 11/2 to 2 teaspoons of chlorine shock per 100 gallons of water. This should get the water nice and clear and ready for defoaming. You might even find this disperses the foam, but if it remains, you must go on to the next step.

Remove as much of the foam as you can by hand. I use an old detergent bottle that I sliced a chunk out of, keeping the handle so I can scoop the top surface of the water—this is great for getting rid of bugs too.

This will still leave a thin layer of foam, but it will be much easier to treat.

Mix a solution of water and vinegar in a ratio of 10:1. I recommend starting with a 5-gallon container. This is only going on the surface to clear the foam so you’re not trying to change the chemical make-up of the water.

If you have some more available, you can add baking soda to the mix. The recommended ratio is 2 parts vinegar to 1 part baking soda and 9 parts water.

Just remember that vinegar is an acid, and it will reduce the pH of the water. Baking soda will raise the pH slightly, but it will have more of an effect on total alkalinity. Always test the water after adding any product and before getting in.

Another method I discovered is to use an oil-absorbent sponge like the one by Scumbug available on Amazon. You can check out the latest price by clicking on the link.

Just place one sponge on the surface of the water, and it will absorb 40x its own weight in oil. It may take up to a week to clear the foam, but if you’re not in a rush, this might work for you.

What can I use instead of a defoamer?

If you don’t want to use a defoamer and oil-absorbent sponges are out of the question, you could try a water clarifier such as the MAV AquaDoc Spa Clarifier on Amazon. Just click on the link to check it out.

MAV AquaDoc will eliminate cloudy water and remove foam from the surface fast. It works by causing the micro-contaminants—the tiny particles that can pass through most filters—to cluster and become large enough to be caught in the fibers of the filter.

It’s easy to use, but make sure the filter is clean before you start.

Just add 2 ounces of MAV AquaDoc per 250 gallons of spa water. Turn on the circulation system and leave the jets open until the foam disappears and the water is crystal clear. Do this twice a week to clear all contaminants from the water.

MAV AquaDoc is compatible with both chlorine and bromine sanitizers, and it works great on saltwater hot tubs too.

Final thoughts

Foam on the surface of the water in your hot tub is a sign that something is not right. Hopefully, this article has shown you what might be the problem and how best to treat it.

You don’t need harsh chemicals, and there are natural remedies out there, but there are some proprietary products on the market that will do the job much faster without altering the chemical balance of the water.

Just check your chemical levels and pH levels on a regular basis, use a spa shock weekly, never put bubble bath in a hot tub, change the water every 3 months, and you’ll likely never encounter a lot of foam.

High pH is a sure-fire way to lead to foam formation. So adjust that quick if you see it!

Ready to Spend Less Time On Maintenance and More Time Enjoying Your Hot Tub?

Let’s face it. Balancing the water, cleaning filters, dealing with rashes, and trying to figure out which chemicals to buy and add can make you feel more like a chemist than someone who just wants to relax after a long hard day!

That’s exactly why The Hot Tub Handbook and Video Course is so valuable!

This is from Matt over at Swim University and he developed it for people looking to save money, time, and frustration. His tips on chemicals can save you $100/year just by making sure you buy only what you need.

So if you’re ready to stop being confused or frustrated with your hot tub and start spending more time in it, check out The Hot Tub Handbook and Video Course.

Just click that link to learn more on their website.

Image by Myriams-Fotos from Pixabay

As an Amazon Associate, I may earn a small commission from qualifying purchases if you click on Amazon from my site and choose to make a purchase. You can read my complete affiliate disclosure for more details.

Jeff Campbell
Latest posts by Jeff Campbell (see all)